[Chandler-dev] added support for --repair

At Bryan's request, I added support for yet another command line option,
called --repair, that runs 'check and repair' on the latest version of a
repository view and repairs check() failures -- currently broken indices
only.
This is an alternative to --undo or re-starting from scratch.
The --backup, --repair and --undo command line options can be used in tandem.
Their order is not significant as --backup is run before --repair and
--repair is run before --undo.
Examples:
rc -e --backup --repair --undo check
1. the repository is backed up (to where, see chandler.log which lives in
your profile directory whose hiding location is described here:
http://wiki.osafoundation.org/twiki/bin/view/Projects/ProfileDirectory
2. repair what can be (currently broken indices only)
3. if repair didn't succeed in fixing all that is broken, that is, check()
still fails, let undo discard the broken versions
rc -e --backup --repair --undo 1
does the same but discards only the last (newest) version if repair failed,
that is, if check() still fails after repairs.
Andi..
ps: the -e option will cause the output emitted by the code behind these
options to appear on stderr